1. Field of the Invention
The present invention relates to a self light emitting display module provided with a light emitting display panel in which for example organic EL (electroluminescent) elements are employed for pixels as self light emitting elements and drive means to drive and light this panel, and particularly to a self light emitting display module having a function that can generally inspect a state in which a defect is occurring in the self light emitting elements in the light emitting display panel and an inspection method of a defect state in the same module.
2. Description of the Related Art
A display has been installed in many of electronic equipment or the like which have been provided presently, and this display has been necessary and indispensable as a man-machine interface of equipment supporting information-oriented society. In a case where the above-mentioned display is employed in a field in which there is a possibility that trouble in display such as for example of a meter of medical equipment or airplanes and the like may influence a human life, a stricter reliability in a display is required than in a display adopted in consumer equipment such as a portable telephone, car audio, and the like.
For example, regarding injection equipment for a medicine or the like, in the case where a bright leak phenomenon occurs in the scan direction on a portion displaying figures showing an injection amount, a problem that whether a displayed figure is “0” or “8” cannot be determined may occur. A problem which may occur is that pixels of a part on which a decimal point is displayed are not lit so that the place for the figures is erroneously displayed so that the figures are read while this is not being noticed or the like. It is extremely dangerous for a user to keep using the above-described equipment while perceiving display in a troubled state being normal, and it is needless to say that such a state may develop a serious problem.
Thus, in the display employed in the above-mentioned electronic equipment, in a state of semi-finished goods before the product is shipped, a defect state regarding each pixel arranged in a display panel has been inspected to determine whether or not the degree of defect meets the standard of a product into which this display is loaded (for example, see Japanese Patent No. 3437152).
Meanwhile, the invention disclosed in Japanese Patent No. 3437152 is to execute evaluation of each pixel of a display panel in a state of semi-finished goods before the product is shipped, and an object thereof is to provide an evaluation device through which evaluation results having high reliability can be obtained utilizing a drive circuit for inspecting an organic EL display.
In a case where the evaluation device disclosed in Japanese Patent No. 3437152 is utilized, although an effect that an initial defect of a product can be detected to deal with the defect before the display panel having the defect is delivered to a user can be produced, this type of display has a problem that a defect may newly occur in pixels arranged in a display panel while the display unit is in operation after shipment of the product.
Thus, various countermeasures for keeping the extent that such a defect occurs at a minimum to ensure reliability have been adopted. However, to overcome the problem of defect of pixels occurring during the operation of the display or the like or the problem that defect occurs in the above-mentioned drive means or the like, extremely numerous technical problems exist, and we have to say that it is difficult to provide a display module in which the above-mentioned defect does not occur after the shipment of the product.